Due to the geographic coverage nature of wireless service, there are hundreds of thousands of cell towers in the United States. For example, in 2014, it was estimated that there were more than 310,000 cell towers in the United States. Cell towers can have heights up to 1,500 feet or more. There are various requirements for cell site workers (also referred to as tower climbers or transmission tower workers) to climb cell towers to perform maintenance, audit, and repair work for cellular phone and other wireless communications companies. This is both a dangerous and costly endeavor. For example, between 2003 and 2011, 50 tower climbers died working on cell sites (see, e.g., www.pbs.org/wgbh/pages/frontline/social-issues/cell-tower-deaths/in-race-for-better-cell-service-men-who-climb-towers-pay-with-their-lives/). Also, OSHA estimates that working on cell sites is 10 times more dangerous than construction work, generally (see, e.g., www.propublica.org/article/cell-tower-work-fatalities-methodology). Furthermore, the tower climbs also can lead to service disruptions caused by accidents. Thus, there is a strong desire, from both a cost and safety perspective, to reduce the number of tower climbs.
Concurrently, the use of unmanned aerial vehicles (UAV), referred to as drones, is evolving. There are limitations associated with UAVs, including emerging FAA rules and guidelines associated with their commercial use. It would be advantageous to leverage the use of UAVs to reduce tower climbs of cell towers. US 20140298181 to Rezvan describes methods and systems for performing a cell site audit remotely. However, Rezvan does not contemplate performing any activity locally at the cell site, nor various aspects of UAV use. US 20120250010 to Hannay describes aerial inspections of transmission lines using drones. However, Hannay does not contemplate performing any activity locally at the cell site, nor various aspects of constraining the UAV use. Specifically, Hannay contemplates a flight path in three dimensions along a transmission line.
Of course it would be advantageous to further utilize UAVs to actually perform operations on a cell tower. However, adding one or more robotic arms, carrying extra equipment, etc. presents a significantly complex problem in terms of UAV stabilization while in flight, i.e., counterbalancing the UAV to account for the weight and movement of the robotic arms. Research and development continues in this area, but current solutions are complex and costly, eliminating the drivers for using UAVs for performing cell tower work.
3D modeling is important for cell site operators, cell tower owners, engineers, etc. There exist current techniques to make 3D models of physical sites such as cell sites. One approach is to take hundreds or thousands of pictures and to use software techniques to combine these pictures to form a 3D model. Generally, conventional approaches for obtaining the pictures include fixed cameras at the ground with zoom capabilities or pictures via tower climbers. It would be advantageous to utilize a UAV to obtain the pictures, providing 360 degree photos from an aerial perspective. Use of aerial pictures is suggested in in US 20100231687 to Armory. However, this approach generally assumes pictures taken from a fixed perspective relative to the cell site, such as via a fixed, mounted camera and a mounted camera in an aircraft. It has been determined that such an approach is moderately inaccurate during 3D modeling and combination with software due to slight variations in location tracking capabilities of systems such as Global Positioning Satellite (GPS). It would be advantageous to adapt a UAV to take pictures and provide systems and methods for accurate 3D modeling based thereon to again leverage the advantages of UAVs over tower climbers, i.e., safety, climbing speed and overall speed, cost, etc.
In the process of planning, installing, maintaining, and operating cell sites and cell towers, site surveys are performed for testing, auditing, planning, diagnosing, inventorying, etc. Conventional site surveys involve physical site access including access to the top of the cell tower, the interior of any buildings, cabinets, shelters, huts, hardened structures, etc. at the cell site, and the like. With over 200,000 cell sites in the U.S., geographically distributed everywhere, site surveys can be expensive, time-consuming, and complex. The various parent applications associated herewith describe techniques to utilize UAVs to optimize and provide safer site surveys. It would also be advantageous to further optimize site surveys by minimizing travel through virtualization of the entire process.
Wireless coverage testing is important for service providers and consumers—it is used for marketing purposes (who has the better network) and for engineering purposes (where do we need to augment or improve our coverage). Conventional approaches to wireless coverage testing utilize so-called drive tests where wireless coverage is tested by physically driving around a region with a test device and making measurements along the way. The conventional approaches are limited to ground coverage, not aerial coverage, as conventional drive tests are just that—driven by a vehicle on the ground. The Federal Aviation Administration (FAA) is investigating use of the wireless network in some manner for air traffic control of UAVs. Thus, there is a need to extend conventional drive tests to support wireless coverage testing above the ground.